The present disclosure relates to a method, an apparatus, a system and a computer program for controlling an electric power system, including controlling the voltage on the distribution circuits with respect to optimizing voltage solely for the purpose of making the electrical delivery system compatible with high variation distributed generation and loads. More particularly, the disclosure relates to a method of optimizing variable load compatibility using advanced metering infrastructure (“AMI”)-based data analysis. This method enables the direct control of customer level secondary voltages to optimally enable the electric energy delivery system (EEDS) to maximize its capability to accommodate large amounts of individual and aggregate load variability. The method executes this variable load voltage control using the secondary AMI-based measurements, significantly improving the reliability of the customer voltage measurement and level, enabling the EEDS operator to improve the reliability of customer voltage performance for these types of distributed generation and loads.
The method of the disclosed embodiments is separated into four major steps. The first is to locate the loads with common secondary voltage connections based on voltage correlation analysis from historical data, typical impedances of secondary conductors, and GPS coordinates to estimate distances. The second is to use a novel method to electronically “build” the primary load connections by correlating with the estimated primary voltage drop. The third is to characterize the loads in terms of a linear model. The fourth is to control the independent voltage control variables to select the optimum operation level to maximize the circuit's ability to successfully respond to the load variation affect using a novel method of building a piecewise linear regression model and center the regression model using the independent voltage variables. This optimizes the ability of the circuit to respond to high variation loads.
Electricity is commonly generated at a power station by electromechanical generators, which are typically driven by heat engines fueled by chemical combustion or nuclear fission, or driven by kinetic energy flowing from water or wind. The electricity is generally supplied to end users through transmission grids as an alternating current signal. The transmission grids may include a network of power stations, transmission circuits, substations, and the like.
The generated electricity is typically stepped-up in voltage using, for example, generating step-up transformers, before supplying the electricity to a transmission system. Stepping up the voltage improves transmission efficiency by reducing the electrical current flowing in the transmission system conductors, while keeping the power transmitted nearly equal to the power input. The stepped-up voltage electricity is then transmitted through the transmission system to a distribution system, which distributes the electricity to end users. The distribution system may include a network that carries electricity from the transmission system and delivering it to end users. Typically, the network may include medium-voltage (for example, less than 69 kV) power lines, electrical substations, transformers, low-voltage (for example, less than 1 kV) distribution wiring, electric meters, and the like.
The following, the entirety of each of which is herein incorporated by reference, describe subject matter related to power generation or distribution: Engineering Optimization Methods and Applications, First Edition, G. V. Reklaitis, A. Ravindran, K. M. Ragsdell, John Wiley and Sons, 1983; Estimating Methodology for a Large Regional Application of Conservation Voltage Reduction, J. G. De Steese, S. B. Merrick, B. W. Kennedy, IEEE Transactions on Power Systems, 1990; Power Distribution Planning Reference Book, Second Edition, H. Lee Willis, 2004; Implementation of Conservation Voltage Reduction at Commonwealth Edison, IEEE Transactions on Power Systems, D. Kirshner, 1990; Conservation Voltage Reduction at Northeast Utilities, D. M. Lauria, IEEE, 1987; Green Circuit Field Demonstrations, EPRI, Palo Alto, Calif., 2009, Report 1016520; Evaluation of Conservation Voltage Reduction (CVR) on a National Level, PNNL-19596, Prepared for the U.S. Department of Energy under Contract DE-AC05-76RL01830, Pacific Northwest National Lab, July 2010; Utility Distribution System Efficiency Initiative (DEI) Phase 1, Final Market Progress Evaluation Report, No 3, E08-192 (7/2008) E08-192; Simplified Voltage Optimization (VO) Measurement and Verification Protocol, Simplified VO M&V Protocol Version 1.0, May 4, 2010; MINITAB Handbook, Updated for Release 14, fifth edition, Barbara Ryan, Brian Joiner, Jonathan Cryer, Brooks/Cole-Thomson, 2005; Minitab Software, http://www.minitab.com/en-US/products/minitab/ Statistical Software provided by Minitab Corporation.
Further, U.S. patent application 61/176,398, filed on May 7, 2009 and US publication 2013/0030591 entitled VOLTAGE CONSERVATION USING ADVANCED METERING INFRASTRUCTURE AND SUBSTATION CENTRALIZED VOLTAGE CONTROL, the entirety of which is herein incorporated by reference, describe a voltage control and energy conservation system for an electric power transmission and distribution grid configured to supply electric power to a plurality of user locations.